People say you are what you eat. In fact, what you eat affects far beyond just yourself and more than most people imagine. Several scientific studies state that eating meat is environmentally unfriendly, and that a diet based on vegetables and fruits is better for both your health and every aspect of the earth. But you may ask: how is that possible?

The answer is simple. As energy flows through the food chain, around 90 percent of it is lost while moving from one step to another.  If we decide to eat vegetables, fruits, cereals and harvest foods directly, we are saving 10 times more resources than choosing to eat meats like pork, chicken or beef although they are significant differences among them.

Feeding a herbivore, such as a cow, requires breeding it until it’s ready for slaughter. A cow will eat grain and drink water every day. Skipping one level can save up to 10 times more land, water, fertilizer, petrol for transportation, and so on.

According to a study from 2006, the United Nations Food and Agriculture Organization (FAO) estimated that livestock production generates nearly a fifth of the world′s greenhouse gases. The numbers may seem high, but the crux of the matter can be found in what scientists call the “CO2 equivalent.”

Knowing that gases vary in greenhouse potency, every greenhouse gas expressed has an amount of CO2 with the same global-warming potential. For instance, when cows digest their food, they emit methane. Their manure, methane, and nitrous oxide have roughly 23 times the global-warming potential of CO2.

The FAO found that current production of meat contributes between 14 and 22 percent of the 36 billion tons of CO2-equivalent greenhouse gases the world produces every year. In 1999, Susan Subak, scientist at the University of East Anglia in England, found that, depending on the production method, cows emit between 3.6 and 6.8 kilograms of CO2 into the atmosphere for each kilogram of beef produced.

Gidon Eshel and Pamela A. Martin, from the University of Chicago, calculated that if Americans were to reduce meat consumption by just 20 percent, it would be as if they switched from a standard sedan to the ultra-efficient Prius, which generates 89 grams of CO2 per kilometer.

For example, the production of 2.2 pounds of beef is the mass required for the equivalent amount of carbon dioxide emitted by the average European car every 155 miles. That amount can burn enough energy to light a 100-watt bulb for nearly 20 days.

Another study, led by Akifumi Ogino of the National Institute of Livestock and Grassland Science in Tsukuba, Japan, showed the effects of beef production on water acidification and eutrophication owing the huge amount of manure that livestock farms produce at an undesirable output from meat production.

A bad management of animal´s manure often leads to water contamination as the non treated manure uses to disintegrate into the soil and after poisoning underground streams of water or be discharged in rivers of lakes directly. But this does not stopped many people from eating meat.

Beef consumption has increased both as population increases and as people in developing countries, such as south-east Asia, are increasing their living standards, allowing themselves to shift from a diet of rice and soya to more sophisticated foods as beef. The annual beef consumption per capita varies from 120 pounds in Argentina and 92 pounds in the U.S., to only a pound in Moldova.

The world average is about 22 pounds per person a year, according to the FAO for the year 2003. You can make a difference; think what is better for you, what is better for your environment and take a step forward. You don’t need to become a vegan. Just think about it, and the next time you go to a restaurant, choose the salad instead of the steak.

This is not about huge personal changes, it is about small, continuous social changes. The Earth will surely appreciate it.